[sdiy] complex gesture control ?

[Fernando de Izuzquiza]

Hi all. I've been thinking about this for some time now:
I think it would be a useful addition to controllers, to have a simple circuit that can generate
gate/trigger/"velocity" when playing from a  sensor-type controller (joystick, ribbon, photocell,
IR, ....any sensor)
The joystick may be a good example: you are sending CV from any position; using A, you open a gate
whenever the joystick is in motion. When steady for more than, say, 300ms, the gate goes low, and so
on.
With  B, you send a trigger whenever you make a fast gesture (sensitivity preset), and at the same
time, a CV proportional to the "strength" of that gesture (how fast did you change the stick
position)

A- Time based gate:
If there is no change in CV after a preset waiting time, it goes low. Then, open the gate whenever
any change in CV is detected. Close the gate again when no activity is detected for the w. time, and
so on. (A comparator is not enough because you need to sense motion at any position=any CV)

B- "velocity" + trigger:
If you change CV fast enough, a trigger is sent, and also a CV proportional to how fast the
CV changed (as in PAiA Theremax, see notes at Theremax pages)

I made a very simple implementation of A in software (Max-MSP) some time ago. It was useful in order
to open and close vcas or activate the event/s I was controlling, and "mute" all activity when no
event was produced from controller (photocells and/or theremax)
B idea is from Theremax. I built one, and found great the gate and velocity implementation (when
using Theremax as a CV controller)
Implementing this two ideas will give us: 1. controller's CV output  2. an "event" gate  3. a sort
of "staccato event" trigger and 4. a "velocity" equivalent CV, producing lively control out of just
one controller.

How could we implement this two ideas using comparators, gate delays... circuits we already have.
Or build simple circuits... any idea wise men?

Fernando


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